Can this Piston be Salvaged?

[StuGotz]

I've NEVER seen an engine with piston damage STOP fast enough to limit damage. Oil passages, journals get clogged rather quickly. Aluminum gets into places it shouldn't.

 

Think this process through before spending money on parts that will get damaged again...

 

(((((((just keeping this thread at the top)))))))))))

 

MB>

[realshelby]

Ken, I hate to hear about your low side. Glad you're OK. I too have had to go the cheap route to get a vehicle on the road. Sometimes it works out just fine. As far as the parts of the piston in the sump, I doubt they can be a problem. I understand the boxer has a very deep "sump" to crank measurement. Sounds like a replacement head/jug may be cheaper than all the machine work mentioned to repair the current parts. You'll have to do the math on that one. I would be surprised to see crank/big end rod damage. What I would like to see you inspect closely is the small end of the rod. Sounds like the damage was less from the low side and the real problems came from the curb damage. That would have tried to force the head/jug to the rear to some degree. Connecting rods are not designed to handle much in the way of side loads. If you can reinstall the piston pin look VERY closely for signs that the pin is not absolutely parallel to the engine block mating surface. You may be able to measure this to some degree also. It is very possible the rod is bent to the rear of the bike. But if it is not then there is very little chance the bottom end suffered any damage at all. If this is bent you will know it upon reassembly. If after you get the jug/piston installed try tightening them down slightly without the head somehow. If the motor does not turn freely you have a bent rod! Good luck!

[Ken H.]

Remove the head studs and roll 'em on a good flat table.. this will tell if the block took the big "hit"..

I did this to night and they seem fine.

 

Also when they where installed in the block I checked for squareness of them to the block out at their far end and in both horz. and vertical access all four seem square. Does this tell us anything meaningful?

[Ken H.]

Don't forget that the missing material may well be in the exhaust system and can re-enter the cylinder on negative exhaust pressure pulses, destroying any repair work just done.

Good thoughts. The exhaust system is trash, crushed in on that side, so it won't be going back on. So at least that's not a possibility.

It could also be in the intake tract.

The head's going to be reworked or replaced so intake debris shouldn't be a problem.

[Ken H.]

Call Recycle or Beemerboneyard,

Checked today, Beemerboneyard doesn't have one. Who is the other recyler you are referring to?

[ShovelStrokeEd]

Ken,

Just a thought regarding the connecting rod. You can check it for bending by bringing the wrist pin to a machine shop and having them turn a rod about 6" or so long to the same diameter. Slide the rod through the small end bushing and then, very carefully, measure the distance from the try piece to the face of the cylinder mount on the block. Also, eyeball the relationship to the bore in the block for any sign of twist in the rod. I would venture that anything over 0.010" or so difference, about the best resolution you are gonna get with a dial caliper, would make me suspect of the rod for bending. You might be able to better this accuracy by measurement at BDC with a spacer block or an adjustable parallel mounted on the face of the block. A set of same is available from Starrett for nominal bucks.

[Tony_K]

Call Recycle or Beemerboneyard,

Checked today, Beemerboneyard doesn't have one. Who is the other recyler you are referring to?

 

Found this list with some other bmw salvage locations mixed in with dealers. Not all may be still in business.

 

BMW Specialists

 

Bent Beemer 503 549 9742 (Sisters, OR)

Bent Bike MC Salvage 800 328 8810

Blue Moon Cycle 404 447 6945 (Norcross, GA)

BMW Motorrad 800 9991269, 314 531 4010 (MO)

Bob's BMW 301 924 5155 (Elkridge, MD)

Capital Cycle Corporation 800 642 5100

CC Products 408 559 6602 (CA)

Eurotech 800 845 4022

Luftmeister 800 275 2129, 213 408 0411

Perry BMW Exchange 317 564 6338 (Delphi, IN)

Re-Psycle BMW Parts 614 837 1160 (Carroll, OH)

Recycled Cycles Inc. 208 772 2645 (ID)

Salvage & Used Parts 509 926 5044 (WA)

San Jose BMW 408 295 0205 (San Jose, CA)

Shail's Motorcycles Ltd 604 266 7736 (Vancouver, B.C.)

Speed's Cycle 410 379 0106 (Elkridge, MD)

[ESokoloff]

 

Glad your Ok & hope you get rolling again soon.

[Joe Frickin' Friday]

You have to disasseble the bike off the motor (literally as the rest of the bike is bolted onto the structural support motor) then split the case in half to gain access to the innards. Where I still may have to go...

 

I think you can get away without this PITA step. You have several things that ought to be done, and all can be accomplished IMO without splitting the cases.

 

To do:

 

-extract right piston for weighing.

-examine crank/rod for damage.

-clean any metal debris from sump.

 

HOW to do? Pull right side head, piston, and cylinder. Now you have access to the rod bolts at the crankshaft, and you can remove both connecting rods. This will give you visual access to the crank cheeks, and to the big end of the left conrod; inspect both for galling, witness marks, or other obvious deformation. You may need a small mirror and flashlight to check the crank. If you can't find any obvious signs of impact or deformation on the big end of the left conrod, then the crank is probably OK too, but you may want to reassemble with new bearing shells.

 

You'll probably want to take that left conrod to an engine shop and have them measure for twist, center-to-center, roundness on the holes, etc.

 

While the rods are out, drain the oil from the sump, and take a look in there with a flashlight (and maybe a mirror). See if you can spot any chunks of metal. if there are any puddles that won't drain, get in there with a shop rag, or a small suction hose duct-taped to a shopvac.

 

And of course weight that rightside piston while it's out.

 

For reassembly, you want high-temp RTV between cylinder and crankcase. Make sure you remove every hint of old RTV before reassembly.

 

I'll post other stuff if I can think of it...

[smiller]

I think Mitch's post represents a good compromise between a total rebuilt/replacement and a quickie repair. Pulling the other jug isn't that much work and would enable you to get the rod out in order to examine it more properly, check the crank journals, weight the opposite piston, etc. If all checks out you will be more confident in the repair.

[Ken H.]

I think Mitch's post represents a good compromise between a total rebuilt/replacement and a quickie repair. Pulling the other jug isn't that much work and would enable you to get the rod out in order to examine it more properly, check the crank journals, weight the opposite piston, etc. If all checks out you will be more confident in the repair.

Yeah, as much as a loath the thought, I'm thinking you all are right. A couple respected people on the IBMWR list are basically saying the same thing. Guess I'll start pulling the other side apart tonight. Sigh...

[finallyabeemer]

Big ouch. Glad you're OK, and impressed to see you focusing on how to fix rather than lamenting the past. I can relate.

 

As a mechanical engineer, garage rat, and an ex-starving college student who has performed repairs and rebuilds from the absolute minimum cost version to the no-limits versions, I find myself agreeing with Mitch. That feels very near the asymptote of the cost/benefit curve.

 

Doing that does not add much cost (another side's worth of gaskets) while giving you the ability to check much more.

 

I am the manager overseeing our quality lab, and will offer up my surface plate, precision measuring equipment, and skills to measure and compare your rods if you would like. Unfortunately, I do not have a CMM, but with time, I can definitely confirm that they are straight to within a thou or two. I could weigh your right side piston to within a gram or so as well.

 

Us DIY'ers gotta support each other!

[Ken H.]

Couple of people asked about where I am on my damaged engine, so:

 

The status at the moment is waiting for parts. Some stuff is in, but not enough for me to start reassembling the engine, still need some O-rings and such.

 

I ended up pulling apart the right/undamaged side to so as to be able to weigh the good piston, which was a even 570g. But only this past Tuesday did Chicago BMW sort out what was (hopefully) the correct one to order, as several of the listed ranges covered 570g. There is still some question if I will have to take both of them to a machine shop to have exactly weight matched. Guess I won't know until I get the new one and see how close it is to 570.

 

ISFA other damage, there is none that I can tell. The rods spec'ed out the same to each other, the rod bearings don't show any damage, nor does the crankshaft. So I'm hopeful (or crazy?), and I'm going to put it back together without splitting the case and see what happens.

 

My biggest worry remains missing metal bits. It seems like I still have some aluminum from the piston skirt that despite two flushings of the case is unaccounted for.

 

I suspect it will be after the holidays at this point before I get all the parts and have the time to get back on it. Oh well, snow flurries expected here in the next couple of days anyway.

 

Here's hoping!

[ShovelStrokeEd]

Ken,

If or when you take the pistons to have them weight matched, be sure you bring it to someone with race engine building experience. Weight removal, even a couple of grams, if done in the wrong place can seriously weaken the piston. Make sure they radius the edges of the removal area, especially if they take material from the pin bosses. A sharp edge there can leave a stress riser.

 

PS, bring the wrist pins with you as well.

 

When refitting, don't forget to check ring end gap. 0.004" per inch of bore is normal. If adjustment is needed, buy a gap filer tool and a couple of india stones for deburring.

[SANTA]

Ken; glad you faired better than the bike. how many mi on the bike?

 

the most cost effective route is to replace the engine, i'd expect in your case that its got a few mi, so i'd be temped to go with a beemerboneyard complete engine,

 

in my book Ed's the engine guy, but i'll add my $0.02... based on my time in the shop.

 

to order and match a piston will become a real pain. you would need to send the left rod, crank and maybe even the case out for inspection, and the piston would have to be been cleaned to like new, because of the weight tolerance required, you don't really want to start with anything having buildup on it.

 

the inspection would tell you if there is any other damage, rebuilding if possible would take some time, a used core if available would get you back on the road in short order, you can take your time to rebuild it if the remain parts are still in spec

[Ken H.]

Hi Claus,

 

48,000 Km on the bike.

 

Surprisingly I have come up completely blank on finding a used engine for this bike. I've checked with every breaker I've ever heard of on this continent, and they have additional feelers out, and a big fat nothing. So I'm kind of forced to either get this one back up or go the new engine or new short block route. Big bucks $US4160 for the complete engine. Which would effectively end my riding because I just plain don't have that kind of $$ sitting around.

 

I did de-carbon (a lot on it actually ) the good piston before having it weighed, so at least on that part I'm true.

 

So I guess parts arrival and time will tell the next chapter of the tale!

[SANTA]

Okay so got it appart this far... now it's Tim-the-toolman Taylor time... TURBO TURBO TURBO 300HP 10,000rpm

 

one of the guys over on the r1100s site blew his motor just awhile ago, he was pushing the envelope, we are all cheering for you, as you go were meer mortals fear to tread..

 

what about some pictures?

[Ken H.]

Okay so got it appart this far... now it's Tim-the-toolman Taylor time... TURBO TURBO TURBO 300HP 10,000rpm

Probably not, apparently I'm quite capable of crashing it with the HP it has now.

what about some pictures?

Well here's its current state, nothing but long bolts sticking out each side.

 

 

[ShovelStrokeEd]

Somethin' to do while you're waiting for the rest of the parts to show up.

 

Remove the front cover from the motor and dismantle/inspect the oil pump. You did mention you are still missing some aluminum, nicht var? Oil pumps do not digest that stuff very well. Don't want the bike having a sore tummy once you get all the shiny new stuff back in there.

[bakerzdosen]

And only Ken would color match his oil filter to his bike...

 

(Yup - we're all rootin' for you on this one Ken.)

[Ken H.]

Ken,

If or when you take the pistons to have them weight matched, be sure you bring it to someone with race engine building experience. Weight removal, even a couple of grams, if done in the wrong place can seriously weaken the piston. Make sure they radius the edges of the removal area, especially if they take material from the pin bosses. A sharp edge there can leave a stress riser

OK some of the parts are starting to show up finally, including a new piston. My question now is on the weight match, how close is close enough? The old right side one weighs 570 grams, the new left one 566 grams. Is a 4 gram difference too much and I'm off to the machine shop?

[Jim VonBaden]

Ken,

If or when you take the pistons to have them weight matched, be sure you bring it to someone with race engine building experience. Weight removal, even a couple of grams, if done in the wrong place can seriously weaken the piston. Make sure they radius the edges of the removal area, especially if they take material from the pin bosses. A sharp edge there can leave a stress riser

OK some of the parts are starting to show up finally, including a new piston. My question now is on the weight match, how close is close enough? The old right side one weighs 570 grams, the new left one 566 grams. Is a 4 gram difference too much and I'm off to the machine shop?

 

IIRC the spec is within 10 grams, so I would say you are definitely close enough.

 

That said, have you weighed your rods, rings and bearings for match? Were it me, I would try to get each as close as possible for maximum smoothness. But that is just me.

 

Jim

[Ken H.]

Not a lot of progress on getting it back together yet, the valve guide seals remain on back order.

 

Here's the repaired head with the new welded in lower front valve cover stud and you can see the color difference at the repaired cover seal surface:

 

 

Oh, and per Ed's suggestion I did pull apart the front of the motor and inspect the oil pumps. Didn't find anything.

 

Come on parts! I want to see if this thing is going to run again or not!

[KDeline]

[smiller]

I want to see if this thing is going to run again or not!

It will, good as new. There's a very good mechanic working on it...

[Ken H.]

I want to see if this thing is going to run again or not!

It will, good as new. There's a very good mechanic working on it...

Thanks for the vote of confidence. If I see him I'll tell him.

[KDeline]

I want to see if this thing is going to run again or not!

It will, good as new. There's a very good mechanic working on it...

Thanks for the vote of confidence. If I see him I'll tell him.

 

 

[SHIMHEAD]

Hey Ken (or the unknown mechanic),

One last suggestion. If you could find a borescope to borrow, you might could take one last look in the crankcase for the missing piston pieces by inserting it in the oil drain hole. Likely that the oil pickup would prevent any large pieces from entering the pump, but I still would want to account for as much as possible before I lit that mutha up again! Might even be able to flush out some pieces using a quantity of fresh oil with the plug out. Pretty sure I got my whole two cents in now. GOOD LUCK!

 

SHIMHEAD

[SHIMHEAD]

OOPS!, just looked over the whole thread again, I forgot that the missing piston pieces were on the combustion chamber side! Anyhow, it would be reassuring to see a clean crankcase prior to buttoning her up.

 

SHIMHEAD

[Stan Walker]

One last suggestion. If you could find a borescope to borrow, you might could take one last look in the crankcase for the missing piston pieces by inserting it in the oil drain hole.

 

With the pistons laying on the workbench, I don't think he needs to use the oil drain hole for this.

 

Stan

[Ken H.]

Thanks for the suggestions. I've looked, and prodded, and flushed every nook and cranny I can get to, until I'm just plain tired of looking. Short of splitting the case, I've done everything I can think of, or has been suggested, to find junk left in it.

 

So if I ever get all the parts (why do BMW parts take so long to get??? ), I'm going to put 'er back together, fire 'er up, then presuming it runs right shut it down and do an oil and filter change.

 

Here's hopin'!

[SHIMHEAD]

Well I don't know about the rest of you guys, but the suspense is killing me. Not having had a hexhead apart, nor seen any apart other than your pictures, I really don't know what can and can't be seen throught the open cylinder to crankcase junction. However, I do feel that a borescope might allow you to see areas that you couldn't see otherwise. Just a suggestion nonetheless. That is the beauty of this forum, anyone can chime in and two (or many more) heads are always better than one. I'm sure everyone who has posted has your ultimate success in mind. In the end, your bike gets fixed, and we all gain knowledge and understanding. I know I have!

 

Thanks,

SHIMHEAD

[SANTA]

Ken; looks like your making good headway minus BMW... sometimes i find myself taking things apart just to see what makes them tick, in your case you found a better excuse...

 

this stuff is big enough that it can be repaired, and it makes sense due to the lack of other resonably priced options...

 

hang in there we're all pulling for you

 

[Ken H.]

I really don't know what can and can't be seen through the open cylinder to crankcase junction.

Interestingly, not much. The 1200 hexhead block/case has a, out of a lack of a better term, 'false floor' in it just below the crankshaft. The casting divides the block/case into an upper and a lower chamber. With a one-way oil return valve/flap between them. So looking into the opening where the cylinder is removed doesn't allow you to see down to the auxiliary shaft, oil pumps, sump area etc.

[ShovelStrokeEd]

Hmmmm, cast in windage tray, good idea.

[Ken H.]

Yes, the change is also reflected in the change in the crank case ventilation pick up point. Formally from the space between the rear crankshaft seals, now from the left cylinder head. To better accommodate the air pumping action that happens in the case from the pistons moving in/out in sync would be my guess.